Astro i18n in 2026: The Complete Guide From ui.ts to Edge-Native KV

I needed to ship EdgeKits.dev in four languages. The first 40% of the work was easy: configure i18n , sprinkle getRelativeLocaleUrl where needed, organize the folders by locale. The other 60% was a tour through the i18n ecosystem most tutorials politely skip. I started with bundled ui.ts dictionaries - clean enough until they weren't. Then Paraglide, whose client-side tree-shaking is brilliant - until you run the server-side math forward and watch every additional locale and every new namespace